Thermal glycosylation and degradation reactions occurring at the reducing ends of cellulose during low-temperature pyrolysis.
スポンサーリンク
概要
- 論文の詳細を見る
Thermal glycosylation and degradation reactions of cellulose (Avicel PH-101) were studied in the presence or absence of alcohols (glycerol, mannitol, 1,2,6-hexanetriol, 3-phenoxy-1,2-propanediol, and 1-tetradecanol) under N(2) at 60-280°C. In the presence of glycerol (heating time, 10 min), the reducing ends were converted into glycosides when the temperature of the glycerol was >140°C without the addition of any catalysts. A temperature of 140°C is close to that required for the initiation of thermal polymerization (glycosylation). Although the conversion was only around 20% in the range of 140-180°C, the reactivity increased above 200-240°C where the thermal expansion of cellulose crystals is reported to become significant. Finally, all reducing ends were converted into glycosides at 260°C. Such heterogeneous reactivity likely arose from the lower reactivities of the reducing ends in the crystalline region due to their lower accessibility to glycerol, although the reactivity in the non-crystalline region was similar to that of glucose. Alcohols that have a lower OH/C ratio did not react with the reducing ends, suggesting that the hydrophilicity of the alcohol was critical for the glycosylation reaction to proceed. The glycosylated cellulose samples were found to be significantly stabilized against pyrolytic coloration. The results of neat cellulose pyrolysis indicated that two competitive reactions, thermal glycosylation and degradation, formed a dark-colored substance at the reducing ends while the internal glucose units in the cellulose were comparatively stable.
- 2011-02-01
論文 | ランダム
- パス解析法を用いた乳幼児期の咀嚼習慣のモデル化に関する研究
- 口腔粘膜の透過性に関する研究
- UNIX分散自動運用におけるホットスタンバイ自動切り替え
- Resonant Photoconductivitg in n-Type InSb and Its Transport Properties
- 140 水稲の湛水溝付直播法の出芽・苗立ちに関する研究 : 第5報 種子予措における流水浸種処理と発芽